INTERCOMPARISON OF MEASUREMENTS ON EAR PROTECTORS BY SUBJECTIVE AND OBJECTIVE TEST METHODS
Samples of four different types of earmuffs and one type of ear plugs were used to compare attenuation results obtained by five national test laboratories testing to ISO 4869 (subjective method). One laboratory also measured in accordance with the AFNOR standard NF S31-062-1983. The objective measurements on the earmuffs were carried out following ISO/DIS 6290 (draft). Repeated subjective testing of attenuation within one laboratory showed an average spread of 2 dB. The differences between some laboratories increased to 5 dB. The results for the insertion loss (objective method) varied between laboratories by 6 dB. Resonances at low frequencies (100-250 Hz) were detected. The attenuation measurements on ear plugs do not agree better than +/-6 dB either. The ISO test method gave generally tighter attenuation values by 2 dB than the AFNOR method. Recommendations for improvements of the ISO standards are given.
Bibliographic Reference: EUR 10575 EN (1986) FS, 138 P., BFR 450, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989124113400 / Last updated on: 1987-01-01
Available languages: en